Medium Density Fiberboard Panels Research Articles

Utilization of olive mill sludge in the manufacture of fiberboard

The objective of this research was to investigate the utilization of olive mill sludge (OMS) as an alternative to wood in the manufacture of the medium density fiberboard (MDF). The MDF panels were manufactured using standardized procedures that simulated industrial production at the laboratory. Six panel types were made from various mixtures of hardwood fiber/dried OMS flour, 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (by weight) percents, respectively. With increasing OMS flour content, the flexural properties of the panels, modulus of rupture and modulus of elasticity, decreased by 31.0% and 29.2% as compared to panels without OMS flour, respectively. However, the water resistance was improved by the addition of the OMS flour up to 20 wt % content. For example, the thickness swelling and water absorption values of the panels containing 20% OMS flour were 17.3% and 59.5%, while they were found for the panels without OMS flour as 21.5% and 75.6%, respectively. The findings obtained in the study showed that the OMS was capable of serving as lignocellulosic raw material in the manufacture of the MDF.

The ambient aging of wood fiber and its effect on mechanical properties of MDF panels

Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to study ambient-aged wood fibers and their effects on the mechanical properties of medium-density fiberboard (MDF). It was found that MDF made with ambient-aged fibers had poorer mechanical properties than MDF made with fresh fibers; this difference resulted from the alterations of surface characteristics of wood fibers after ambient aging, which led to poor wettability of the urea–formaldehyde (UF) resin applied to the aged wood fibers. After 6 months of ambient aging, the concentration of carbonyl groups in the fibers increased by 144%, while the pH value of wood fiber decreased from 5.2 to 4.7. SEM showed that much more UF resin agglomerated on the surface of ambient-aged fibers and the breakage of MDF made with aged fiber frequently occurred at the resin-fiber interfaces, indicated the poorer wettability of UF resin to fibers due to the decrease in surface energy after aging.

Surface characteristics and overlaying properties of MDF panels made from thermally treated rubberwood fibers

The objectives of this research were to investigate surface characteristics and overlaying properties of medium density fiberboard (MDF) panels, as affected by thermal treatment of the fibers. MDF panels were manufactured from untreated rubberwood fibers and fibers treated at three different temperatures (120, 150, or 180°C) for 15 or 30 min. Contact angle measurements were obtained by using a goniometer connected with a digital camera and computer system. Roughness measurements, average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Ry), were taken from the sanded samples along and across the sandmarks using a fine stylus tracing technique. With the increasing thermal treatment temperature and time of the fibers, surface roughness of the panels decreased, while their wettability and adhesive bonding strength decreased. Statistical analyses showed significant differences in the surface roughness, contact angle, and adhesive bonding strength of the panels following thermal treatment. Based on the findings obtained from this study, the contact angle and surface roughness parameters of the MDF panels made from thermally treated rubberwood fibers can provide a good information on their ability to bond.

Some properties of thin medium density fiberboard panels treated with sunflower waste oil vapor

The objective of this study was to investigate the effect of hot waste oil vapor on some of the physical and bending properties of commercially manufactured thin medium density fiberboard (tMDF) panels. The samples were treated with waste oil vapor at a temperature of 220 °C for 10 and 20 min time durations. Based on the findings in this work, the water absorption and thickness swelling of the samples were improved by the treated panels with hot vapor oil and heat. It appears that the samples had some discoloration as a result of treatment processes. It was also observed that modulus of rupture (MOR) and modulus of elasticity (MOE) of the samples were adversely influenced. However, it seems that the thermal conductivity of the samples enhanced by such treatments. Panel products treated with these processes could have some promising potential in various applications including outdoor use.

Utilization of pine ( Pinus pinea L.) cone in manufacture of wood based composite

Physical and mechanical properties of medium density fiberboards (MDF) made from various mixtures of wood fibers and stone pine ( Pinus pinea L.) cones were evaluated using European standards. MDF panels were manufactured using standardized procedures that simulated industrial production at the laboratory. Six panel types were made from mixtures of wood fiber/cone flour, 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 percents, respectively. Addition of the cone flour into the MDF significantly reduced formaldehyde emission from the panel. In addition, the addition of 10% cone flour also improved water resistance of the MDF panels made using urea–formaldehyde (UF) resin. However, further addition of the cone flour into the panel negatively influenced their water resistance. Flexural properties and internal bond strength decreased with the increase of cone flour content in the panel. The UF resin is the main source of formaldehyde emission from the UF-bonded wood-based panels. Depending on addition of the cone flour in the panels, the formaldehyde emission values ranged from 2.6% to 55.3% lower than the panels made from 100% wood fiber. Based on the findings obtained from this study, pine cone can be used as a renewable biological formaldehyde catcher as an alternative to the traditional formaldehyde catchers for E1 Class MDF manufacture.

Properties of Medium Density Fiberboard Based on Bagasse Fibers

In this study, sugarcane bagasse fiber was used for medium density fiberboard (MDF) manufacturing. The purpose of this study was to determine the effects of maleic anhydride (MA) and press temperature on the mechanical (static bending, modulus of elasticity, and internal bond) and physical properties (thickness swelling, water and steam absorption) of the boards. This study showed that all the MDF panels made from bagasse fibers treated with MA at 190°C press temperature had the highest values among the other types of panels for general purpose boards. In addition, treated fibers at 190°C showed minimum steam absorption. The absorption of steam increased with increase in time from 12 to 120 h in all the treatments. Beyond 120 h no additional absorption of steam was found in any of the six MDF boards. Overall results showed that MDF panels made from bagasse exceed the EN standards for internal bond, modulus of elasticity, and static bending. However, thickness swelling values were higher (poor) than requirements. For this reason, additional work needs to be done on improving the physical properties of particleboard produced from bagasse.

The effect of surface roughness on tensile strength of the medium density fiberboard (MDF) overlaid with polyvinyl chloride (PVC)

The objective of this study is to determine the effect of the surface roughness on the tensile strength perpendicular to the surface of medium density fiberboard (MDF) overlaid with polyvinyl chloride (PVC). The surfaces of the MDF panels were sanded with four different grit abrasives, 220, 240, 280 and 320-grit, to create different roughness values. The roughness of the panel surfaces were determined in accordance with ISO 4288. The MDF panels were laminated with polyvinyl chloride (PVC) using a polyurethane-based adhesive. A total of 70 samples having the dimensions of 50 × 50 mm from the panels were prepared based on EN 326-1. The universal test machine was used for tensile strength. The test results were statistically analyzed and it was found that the sanding process decreases the surface roughness of the MDF and as the grit size of the abrasives increases, the surface roughness decreases. The surface roughness influences the tensile strength perpendicular to the surface of the overlaid samples. The most suitable surfacing type for lower cost and the highest tensile strength is the sanding with the 240-grit abrasive.

Effects of Post Heat-Treatment on Surface Characteristics and Adhesive Bonding Performance of Medium Density Fiberboard

A series of commercially manufactured medium density fiberboard (MDF) panels were exposed to a post-manufacture heat-treatment at various temperatures and durations using a hot press and just enough pressure to ensure firm contact between the panel and the press platens. Post-manufacture heat-treatment improved surface roughness of the exterior MDF panels. Panels treated at 225°C for 30 min had the smoothest surface while the roughest surface was found for the control panels. Wettability and the adhesive bonding strength between veneer sheet and panel surface were decreased as post-treatment press temperature increased. A significant relationship (R 2 = 0.92) existed between contact angles and adhesive bond strength.

Detection of Induced Damage in Medium-Density Fiberboard Panels Using a Neural Network Method

This research assessed the feasibility of using a neural network to detect induced and interior damage to small samples of medium-density fiberboard (MDF). The neural network was a 3-layer back-propagation network. The undamaged stress wave frequency spectrum patterns were used to train the neural network. In a previous study, we successfully used the trained patterns to evaluate low levels of damage in samples of MDF onto which various percentages of their estimated failure loads were applied. In this experiment, after introduction of grooves on the surface or a hole through the center of the samples, a small change in the wave patterns occurred. The neural network has the unique ability to train itself using data to recognize spectral patterns and was successfully used to detect structural damage.

Influence of relative humidity on surface quality and adhesion strength of coated medium density fiberboard (MDF) panels

The objective of this study is to evaluate surface roughness and adhesion strength of commercially manufactured medium density fiberboard (MDF) panels as function of relative humidity exposure levels. Surface roughness of the samples conditioned at 65%, 75% and 85% relative humidity was measured using a surface profiler. Adhesion strength of the samples coated with polyurethane finish was also determined by employing pull-off type test set up. Roughness values of the panels increased as they are exposed to higher relative humidity levels ranging from 65% to 85%. The highest adhesion strength value was found as 2.20 N/mm 2 for the samples made from unrefined fibers exposed to 65% relative humidity. Majority of the failures took place within adhesion line between coating and the substrate with a very limited torn fibers. Overall adhesion strength characteristics of the samples adversely influenced by increased value of relative humidity exposure.

Detection of Structural Damage in Medium Density Fiberboard Panels using Neural Network Method

This research assessed the feasibility of using a neural network to detect low levels of damage in small samples of medium density fiberboard (MDF). The neural network was a three-layer back-propagation network. The undamaged stress wave frequency spectrum patterns were trained by the neural network. The trained patterns were then compared to stress waves patterns taken from MDF samples loaded to various percentages of their estimated failure load. In this experiment, if an application load is below the proportional limit, a small change in wave patterns occurs. The neural network has the unique ability to train data to recognize spectral patterns and has been used with success for the detection of structural damage.

Mechanical properties of wood plastic composite panels made from waste fiberboard and particleboard

AbstractThe possibility of producing wood‐plastic panels using a melt blend/hot press method was studied in this research. The studied panels were compared with conventional medium density fiberboard (MDF) and particleboard (PB) panels. Wood‐plastic panels were made from high density polyethylene (as resin) and MDF waste and PB waste (as natural fiber) at 60, 70, and 80% by weight fiber loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistances, and impact strength were studied. Results indicated that the mechanical properties of the composites were strongly affected by the proportion of the wood flour and polymer. Maximum values of flexural modulus of wood plastic panels were reached at 70% fiber content. Flexural strength, screw and nail withdrawal resistance, and impact strength of wood plastic composites declined with the increase in fiber content from 60 to 80%. This was attributed to the lack of compatibility between the phases. The produced panels outperformed conventional PB panels regarding their mechanical properties, which were acceptable when compared with MDF panels as well. The best feature in the produced panels was their screw withdrawal resistance, which is extremely important for screw joints in cabinet making. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers

Overlaying properties of fiberboard manufactured from bamboo and rice straw

In this study, surface characteristics of overlaid medium density fiberboard (MDF) panels manufactured from bamboo ( Dendrocalamus asper) and rice straw ( Oryza sativa) were evaluated. Experimental panels were manufactured from two types of raw materials. Samples with dimensions of 15 cm × 15 cm both types of panels were overlaid with decorative paper with a density of 0.75 g/cm 3 using urea formaldehyde resin as a binder. Roughness measurements were randomly taken from the surface of overlaid samples using a fine stylus profilometer. Three roughness parameters, average roughness ( R a), mean peak-to-valley height ( R z), and maximum roughness ( R max) were used to evaluate surface characteristics of overlaid samples conditioned at 55% and 92% relative humidity levels. Statistical analysis revealed that no significant difference was found between roughness values of panels made from two types of raw materials. When the samples were exposed to 92% relative humidity both types of specimens had significantly higher values of R a, R z, and R max than those of measurements taken at 55% relative humidity. The stylus method is able to detect differences in surface roughness of overlaid panels that can occur due to changes in environmental conditions. Initial findings of this study suggest that both non-wood under-utilized species can be considered as raw material to manufacture value-added MDF panels as substrate for overlaying without having any adverse influence on their surface quality.

Physical and mechanical properties of flame retardant urea formaldehyde medium density fiberboard

Medium density fiberboard (MDF) is one of the widely used wood-based panels to manufacture building components such as furniture units for interior applications. Although MDF is an excellent product it is prone to fire hazard which should be enhanced using flame retardants during its manufacture. Properties of the flame retardant urea formaldehyde (UF) MDF made using a dry process from rubberwood fibers were investigated. Flame retardant chemicals that were evaluated include sodium aluminate, zinc borate and aluminum trihydrate, which were incorporated with rubberwood fibers to manufacture experimental MDF. Four concentration levels, 10%, 15%, 20% and 30% of fire retardants and 15% urea formaldehyde resin based on oven dry fiber weight were used to manufacture experimental panels. Physical and mechanical properties including thickness swelling, water absorption, bending characteristics, and internal bond strength of the samples were determined. Flame retardant properties of the panels were also investigated using a Cabinet Method along with char index, weight loss and size of ellipse area. Finally, thermogravimetry method was employed to analyze thermal properties of the MDF panels. The results showed that thickness swell and water absorption decreased as the flame retardant increased. The MOR was not affected by the flame retardant treatment for boards bonded with urea formaldehyde resin. The internal bond strength showed a small reduction compared with the controls as the flame retardant chemicals increased but not for boards treated with 5% aluminum trihydrate. When the concentration of flame retardant chemicals increased to 30%, the internal bond generally decreased. Char index, area of ellipse and weight loss reduced as the percentage of flame retardant increased. Sodium aluminate showed the best performance in reducing thermal degradation followed by aluminum trihydrate and zinc borate. Aluminum trihydrate cured closely resemble that of the control during the gelation test.

Effect of compression wood on dimensional stability of medium density fiberboard

This study evaluated the effect of compression wood on dimensional stability of medium density fiberboards (MDF) manufactured from fiber furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Two panel types were manufactured from two different compression wood (CW) portion / normal wood (NW) portions in the furnish, 75/25 and 10/90, respectively. Linear and thickness variations of the panels exposed to various relative humidites at 20 °C, linear expansion/contraction and thickness swelling/shrinkage, were measured according to the procedures defined by DIN EN 318 (2005) standard test method. Panels made from fiber furnish containing 75% the CW had higher linear expansion and linear contraction values with an average value of 0.286% and 0.247% than those of panels made from fiber furnish containing 10% the CW with an average value of 0.184% and 0.152%, respectively. As for thickness swelling and thickness shrinkage properties, panels made from fiber furnish containing 75% the CW had the thickness swelling and thickness shrinkage values with an average of 5.042% and 4.402% while panels made from fiber furnish containing 10% the CW had the values with 3.621% and 2.861%, respectively. Consequently, based on the findings obtained from this study, expansion and swelling properties of the MDF panels were negatively affected by compression wood increase.

Chicken Feather Fiber as an Additive in MDF Composites

Medium density fiberboard (MDF) panels were made with aspen fiber and 0-95% chicken feather fiber (CFF) in 2.5%, 5%, or 25% increments, using 5% phenol formaldehyde resin as the adhesive. Panels were tested for mechanical and physical properties as well as decay. The addition of CFF decreased strength and stiffness of MDF-CFF composites compared with that of all-wood control panels. However, MDF-CFF panels showed a marked improvement in resistance to water-soak absorption, which provided limited protection against decay fungi. This benefit was probably related to the hydrophobic keratin in the CFF. Further research is focused on the thresholds of CFF required to decrease thickness swelling and increase water resistance.

Effect of boron treatment on surface characteristics of medium density fiberboard (MDF)

Abstract The objective of this study is to determine surface characteristics of medium density fiberboard (MDF) panels manufactured using various boron compounds which have fire retardant effects. The surface roughness of the panels were measured using a fine stylus technique. Three roughness parameters, namely average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) were determined from the surface of the samples. Roughness measurements were taken from both sides of the specimens along and across the sandmarks over 15.2 mm tracing span. It was found that control panels had smoother surface than those of the other panels manufactured with boron compounds. Based on initial results of this study average Ra, Rz and Rmax values were found as 7.73 μm, 56.29 μm and 74.11 μm for the panels produced with 3% zinc borates (ZnB) and 8.14 μm, 60.87 μm and 76.73 μm for 5% zinc borates (ZnB), respectively. It appears that roughness values of the samples increased with increasing chemical concentration used in panel manufacturing.

Manufacture of medium density fiberboard (MDF) panels from rhododendron ( R. ponticum L.) biomass

Rhododendron has invaded the understory layer of the forests throughout the Black Sea Region of Turkey with substantial biomass potential. This study was conducted to evaluate the suitability of Rhododendron fiber for medium density fiberboard (MDF) production. For the evaluation, rhododendron and industrial wood compositions at different mixture rates were compared for some of the chemical properties, such as holocellulose, alfa-cellulose, lignin and ash contents, alcohol–benzene, solubility in dilute alkali (1% NaOH), and hot- and cold-water solubility. In addition, rhododendron fiber properties such as fiber length, diameters and cell wall thickness were determined. For the experiment rhododendron and commercially manufactured chip ( Pinus sylvestris L. and Quercus robur L.) with 11% moisture content were used. The mixing ratios of rhododendron with commercially manufactured chip were 100:0%, 75:25%, 50:50%, 25:75% and 0:100%, respectively. A commercial urea-formaldehyde (UF) adhesive was used as a binder. Chemical properties including; holo-, alfa-cellulose, lignin and ash contents, alcohol–benzene solubility in dilute alkali (1% NaOH), hot- and cold-water solubility were determined. In addition, some of the physical and mechanical properties such as density, thickness swelling (TS), bending strength (BS), modulus elasticity (MOE), internal bond (IB), screw-holding ability perpendicular to the plane of panel, janka hardness perpendicular to the plane of panel properties of MDF were also measured. Chemical composition, solubility of rhododendron-wood are similar to those of hardwoods in general. More over, the values of rhododendron-wood fiber lengths, diameters and cell wall thickness are also in the range of values reported for hardwoods. The results indicated that all the panels met the general-purpose use requirements of TS-EN. Thus, our results suggest that rhododendron biomass can be an alternative raw material for MDF manufacturing.

Effect of thermo-mechanical refining on properties of MDF made from black spruce bark

The effects of thermo-mechanical refining conditions on the properties of medium density fiberboard (MDF) made from black spruce (Picea mariana) bark were evaluated. The bark chips were refined in the MDF pilot plant of Forintek Canada Corporation under nine different refining conditions in which preheating retention time was adjusted from 3 to 5 to 7 min and steam pressure was set at either 0.6, 0.9 or 1.2 MPa. The resulting bark fibers were blended with 12% UF resin (based on oven-dry fiber weight) using a mechanical blender. The resinated fibers were manually formed into fiber mats and hot-pressed into MDF panels using consistent parameters. Two panels for each refining condition were produced, resulting in a total of 18 panels. Analysis of variance (ANOVA) was used to analyze the significance of factors. Regression coefficients and 3D contour plots were used to quantify the relationship between panel properties and the two test factors. The results from this study indicated that the preheating retention time was a significant factor for both modulus of rupture (MOR) and modulus of elasticity (MOE), the steam pressure was a significant factor for internal bond strength (IB), MOR and MOE, whereas both factors were insignificant for thickness swelling, water absorption and linear expansion. The properties of MDF panels were quadratic functions of retention time and steam pressure. Compared to the ANSI standard for 120-grade MDF, most panels with a nominal density of 950 kg/m3 had very high IB (>1 MPa) and acceptable MOR, MOE and dimension stabilities. These results suggest that black spruce bark residues can be considered as a potentially suitable raw material for manufacturing MDF products.

Multivariate modeling of MDF panel properties in relation to wood fiber characteristics

Abstract Properties of medium density fiberboard (MDF) panels in relation to wood and fiber characteristics were investigated. Laboratory MDF panels were manufactured from raw fiber materials from black spruce [Picea mariana (Mill.) BSP.], three hybrid poplar clones (Populus spp.), two exotic larch (Larix gmelinii and Larix sibirica), and a mix of spruce, pine, and fir wood chips. The panels were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), linear expansion (LE), thickness swelling (TS), and water absorption (WA). These properties were analyzed as response variables. As predictor variables, various wood and fiber characteristics were measured, including wood density, pH, base buffering capacity and fiber coarseness. Multiple linear regression analysis was performed to develop functional relationships between panel properties (response variables) and wood fiber characteristics (predictor variables). Ten dummy variables were created and incorporated into the analysis to examine the effects of wood species or type on MDF panel properties. MOR was negatively related to arithmetic fine percentage. MOE was negatively affected by the percentage of small particles (>200 mesh) and wood pH. IB strength was negatively related to arithmetic fine percentage and fiber pH, but positively related to the percentage of small particles (>200 mesh). Wood density affected LE. TS was negatively affected by arithmetic mean fiber length. Arithmetic mean fiber width had a negative effect on panel WA. The presence of dummy variables in the models for MOE, IB and LE indicates that wood fiber characteristics other than those measured in this study significantly affected these panel properties. The study indicates that the refining process can play a significant role in manipulating MDF panel properties.